Wednesday, February 26, 2014

World
is now facing the dread prospect of ‘peak phosphorus’ (the point at which the
production capacity will peak before phosphate reserves gradually run out),
just as we are warned of peak oil, peak coal, or peak uranium. Although, it is
true that energy reserves (oil, coal, uranium) are depleting, they are not
life-binding. Phosphorous, on the other hand, is crucial and elementary to all
life on earth, without which human beings, animals and plants cannot survive. It
is a vital nutrient element in the vigorous growth of plants, other than nitrogen
and potassium. Nitrogen is readily available in the air that we breathe while
there are surplus reserves of potassium to last for centuries. However, it is
estimated that global supplies of phosphorus may start to run out by the end of
this century. With the depleting resources, phosphorus prices will swing, thus
raising additional supply concerns. Still, there are plenty of phosphate rocks
available, but we must act now to conserve it, or it will be too late to revive
our future agriculture.

Importance

Science
fiction author and biochemist Isaac asimov once wrote, “Life can multiply until
all the phosphorus is gone, and then there is an inexorable halt which nothing
can prevent”. Human body requires a minimum consumption of 0.7 gms per day with
their food to stay healthy. Phosphorus plays a key role in cell structuring and
bone and teeth strength. Nerve cells, muscles and DNA molecules- all are
dependent on the phosphate mineral. Also, in plants, it helps in enhancing leaf
growth, yield, disease resistance, and overall health. In short, phosphorus is
the building block of life.

Phosphorus Concentrated Resources

In
fertilizers, phosphorus is the main ingredient in conjunction with nitrogen and
potassium. Phosphorus reserves are concentrated
geographically. Morocco (main exporter, also known as, the Saudi Arabia of
phosphorus), China, South Africa and U.S. are the four countries that control
80% of the world’s usable phosphate reserves and contribute approximately 2/3rd
of the annual phosphorus production. This amount can suffice for about 30 years
of global demand. Trade-wise, increasing dependency on these countries will
only make things worse, resulting in wild swings in tariff and market
disruptions

The Phosphorus Chain

Phosphorous
is naturally present as phosphate ion in phosphorus rocks. It is an
irreplaceable ingredient of life. Weathering releases it into the soil from
where it is absorbed by plants. Phosphorus, then, enters the food chain and
makes its way through every living being. An average human body contains 650
gms of phosphorus.

Phosphorous
is reused approximately 800 times by marine organisms (after reaching water
bodies through weathering and runoff) before sedimentation. After millions of
years of tectonic uplift, it gets back to dry land.

Agricultural Blunders

Harvesting
breaks the natural cycle as it removes phosphorus from the soil. In ancient
farming, human and animal compost was used as fertilizers which were rich in
phosphorus, in turn, replenishing the soil with phosphorus. Modern day
fertilizers limit our ability to return the favor.

On
the other hand, farming also promotes land erosion because of continuous tilling
and crop terracing. This further worsens the situation, leaving the soil
deprived of its vital nutrient.

The Lethal Side of Phosphorus

Huge toxic blue-green algae feeding
on phosphorus

Eutrophication
(an influx of nutrients, often a byproduct of agricultural run-off and sewage
discharge) from eroded soil and human and animal compost end up in lakes and
oceans, where it promotes uncontrolled cynobacterial (or blue-green algae) and
algal growth. After they die, the fossils get collected at the bottom and
consume all the oxygen present, thus choking aquatic life. This results in
death of fisheries creating “dead zones”. U.S. waters have the largest dead
zones off the Mississippi delta.

Solutions

There
are ways to restoring balance to the phosphorus cycle.

·Integrate Farming: Recycling
of human and animal byproducts as fertilizers can be a good start to
refurbishing phosphorus back into the cycle.

·Seeking new sources:
Mining companies should start finding other reserves and research new ways to
extract the mineral.

·Sewage sludge: Sewage
sludge is a rich source of phosphorus and can be processed for making
fertilizers.

·Reduce Erosion:
No-tilling and plowing practices helps to lower soil erosion, leaving more
phosphorus available for the next harvest.

·Innovative ways: Urine
is an excellent source of phosphorus. Sweden has taken initiatives to use this
source by making special urine-diverting toilets. These function by sending
urine to storage tanks for phosphorous recovery.

However,
nature also has a back-up plan for the depleting vital nutrient. Biologist
Mohamed Hijri brings to light a microscopic mushroom (arbuscular micorrhizal
fungi), which is present in soil and helps in making phosphorus readily
available to plant roots by forming a symbiotic relationship.

About Me

Hi, I am Priyanka! Welcome to my corner. I am a mom to 2 wiggly kiddos and a wife to a very patient husband. This is my little nook where I mostly slip in, to share my scientific writings and weird musings!